Purifying phenolaldehyde resins



* highly concentrated solutions- (for instance of 40 percent) ofthecondensation resins in a I alkalies soaps are. adder and carbon dioxide is;-

*- Patented Aug. 21,1928;

U ED STATE-s rmrz s ensnnnsonar'r ran. 11., or an I Il6813 68 i KNE'R, NEAR ERLIN,,GERMANY.

rammes rnENoLaLDEnYnn-Riasms.

., No nrawin a plication filed January ai, 192e,

; The object ofvthe present. invention is; the T obtaining of-phe'nol aldehyde resins," free-of acids and; otherimpurities- There existj principally two classes of processeslin which 5 the said resins are treated with acids. One

of them consists in dissolving the said condensa-tionresins by means of aqlieous alkalies an in precipitating 'them assoluble and .fusible resins by means of acids (see French 1'0 Patent 520,364), Another method consists in treating the said condensation resins with acids whereby the said resins remainsoluble j and fusible..(see German Patents $450,990, Bakelite Gesellscliaft and Hessen of the 2nd v 1-5 March 1920, and 410,858, Bakelite GeSe'llschaft and Hessen of the 5th November 1922) In both cases the resins-retain a art of'the uncombined henols, or other an ersired byroducts. T e byroducts-produced by the y-reaction of. alde ydes' on the phenols are soluble in water inthe presence of alkalies, have a decided odor, and can be transformed into colored products by the action .of light and air, but their chemical constitution is not I .at present known. -'This disadvantage could be-lessened'by carrying out the processes with highly diluted solutions which however cause otherdifiiculties, as for instance the nece's-. sity of. -using large vessels, and difficulties .in collecting" or separating the resins from the liquid.

The

5 the property of rendering substances which,- in' water, are-insoluble or solublewith diiiiculty, soluble in [water (see Neuberg, Bio- I .chemische Zeitsclirift; volume 76 page :107.

and Sitzungsberichte. der preussischen Akad- 0 emie'der -Wissenschaften 1916 page 1034);

- Such salts are soluble'salts ofaromatic acids or of the higher fatty acids, especially sodium ,salts of salicylic acids or, soaps, 1.' e. the potassium .or sodium orammoniumsalts of the I liquid or solid or semisolid fatty-acids, resin acids, wax acids, sulphonated fatsj'or fatty acids, hydroxy 'iattly acids or halogenated 1 fatty acids. Mixtures of thevvarious alkalimetal saltsor soaps may also be used. y f

If, according tothe present invention, to

introduced, it is possible to obtain a precipitate of the resins free of uncombined-phenols present invention consists infcausing p the acids to act on-the condensation resins in the presence of hydrotropic salts (which have Serial No. 82,843, and iii-Germany January 27,1925.

and other impurities absorbable by the-con I densation resins. The salts maybe added be'-' nniaacn, OEERKNER, NEAR. BERLIN, GERMANY, Assromon 'ro naxnnrra fora-during or after the precipitation of the condensation resins by means of acids. If for instance a'soap solution beadded' to the alkal1ne solution-of the condensation resins before the precipitation it can easily .be ascer-i tained from theprop erties of the precipitated resin when sufficient quantities of the precipitant have beenadded, the precipitated resin representing a fine sandlike'powder. The. salts are chosen and their quantities determined so that the resins arep the before'mentioned condition. y

The present process maybe applied to all phenolaldehyde resins,'obtained without condensing agents orwith alkali or acid or both f 1 these condensingagents as far as'the resins ing, water and alk loidal'char'acter'. 'Ewample 1.1 kil ali, also solutions of col-- maldehyde, its-pol mers, or acetaldehyde on a phenol as phenol 1n the proper sense, cresols, naphthols' with basic or acid ,condensa-ting" r j of phenol 'aldev r I hyde resin (obtained by the reaction of foragents) are dissolved in caustic soda solution and water isadded until the volume of the liquid will be'about 2% litres; At ordinary temperature carbon. dioxide. is introduced again fluid. Then no nore carbon dioxide is added and150 cubic centimeters of a5 peradding the soap solution the gel like massbee comes pulverous. and after some ininutesit "until the mass. of high viscosity, has become centage solution ofsoda soap are added. On I v separates from the liquid. The liquid is de- I canted, the precipitate isffiltered, washed with water or 'soapsolution and dried.

, Emample 2.-- 1 kilogram of phenol formaldehyde resin prepared by means of an acid condensating agent is dissolved with caustic Y a 2.5 percentage sodium soapsolu'tion added; Carbon dioxide is introduced quickly until the resinous condensation product is pre-' cipitatedxand is deposited atthe "bottom of fthe vessel. The precipitate and is washed.

E'ieample 3. -1 kilogram of phenolform withfcaustic soda, asin the Example 2'," precipitated by means of earbondioxide and 1 litreof 2.5 percentagesoda soap. solutioinis soda toaetO percentage solutionand 1 liter of is centrifuged m aldehyde resin I prepared partly by alkaline. r and partly by aeidc'ondensatior; is dissolved may be used, as for instance hydrochloricsoap and precipitating t added as soon as the mixture'begins to precipitate. The resin'is precipitated from the liquid,- washed and allowed to dry.

" In the examples also other acids inorganic or organic, gaseous, liquid-or solid, but soluble acid, phosphoric acid, acetic acid, benzoic acid, oxalic acid may be used as precipitants. The acids must be so selected that they do not decompose or deteriorate the resins.

. I claim r 1. A process -for making alkali soluble phenolaldehyde resins free of acids which consists in dissolvin the resins in alkalies, adding-to the solutions obtained so-called .hydrotropic salts which have the property of rendering diflicultly soluble or insoluble substances soluble in water but do not afi'ect the solubility of the phenol resin and precipitating the resins in the presence of the said salts with acids.

2. A process for making alkali soluble resins free of acids which consists in dissolving the resins in alkalies adding alkali metal he resins in the presence of the said alkali metal'soap with acids. 3. A process for, making alkali soluble phenolaldehyde resins free of acids which consists in dissolving the resins in alkalies,

adding sodium soap and precipitating the resins in the presence of the said sodium soap with acids.

4. A process for making alkali soluble resins free of acids which consists in dissolving the resins in alkalies, adding alkali metal soap and precipitating the resins in the presence of the said alkali metal soap with carbon dioxide.

6. A process for making alkali soluble phenolaldehyde resins free of acids which consists in dissolving the resins in alkalies,

adding sodium soap and precipitating the resins in the presence of the said sodium soap with carbon dioxide.

In testimony whereof I hereunto aflix my signature.

FRITZ SEEBACH. 

